What is operating System?
“An operating System (OS) is an intermediary between users and computer hardware. It provides users an environment in which a user can execute programs conveniently and efficiently.”
1. Without a brain, we are not able to do anything at all. An operating system is the brain of a computer.
2. In technical terms, it is software which manages hardware. An operating system controls the allocation of resources and services such as memory, processors, devices and information.
3. A computer system can be divided into four components:
the hardware,
the operating system,
the application software,
and the users,show as following figure:
2. In technical terms, it is software which manages hardware. An operating system controls the allocation of resources and services such as memory, processors, devices and information.
3. A computer system can be divided into four components:
the hardware,
the operating system,
the application software,
and the users,show as following figure:
Characteristics of mordern os??
1. Microkernel architecture: Assigns only a few essential functions to the kernel, including address spaces, interprocess communication, and basic scheduling.
2. Multithreading: The process is divided into threads that can run simultaneously.
3.Thread: Thread is a dispatchable unit of work.It includes a processor context program counter and stack pointer and its own data storage for the stack. It executes sequentially and is interruptable.
4.Process: Collection of one or more threads and associated system resources are known as processes.
5.Symmetric multiprocessing: Standalone computer with multiple processors that share the same memory and I/O facilities connected by a communication bus. All processors can perform the same functions.
6. Distributed operating systems: Provide the illusion of a single main memory and single secondary memory space. It is also used for distributed file system.
7.Object-oriented design: It is used for adding modular extensions to a small kernel. It also enables programmers to customize an operating system without disrupting system integrity.
